I have a SmartSolar MPPT 100/50 with a 400 watt panel connected to a 12v 200ah LifePo battery in our caravan.
Has been charging great in the past but recently it seems to be dropping into float far too early. My battery BMS says 56% SoC per the attached pics but the controller is in float. Some pics of settings attached. What could be the issue here? Hi
What battery settings does the battery manufacturer specify?
Do you use the battery’s BMS or BMV to determine that the battery is not fully charged?
Check what values the lithium profile in Smart Solar specifies.
I think it’s 14.2V and a fixed absorption time of 2 hour.
By then at the latest, the current to the battery should have dropped to 0A and the battery should be fully charged.
I agree when adaptive is on, dropping to float too soon is relative to the discharge level.
See the manual.
Definitely set it to fixed.
The mppt thinks it has done its job. It has reached the target voltage set for the time needed.
The bmv says 77% at 14.1V. so you may need to review that. But try the fixed first and then mess with other stuff.
Time difference between the two screenshots is about 15 minutes so the volt drop to float is pretty precipitous. What loads do you have on? That can also affect proper charging.
No loads at all basically at the moment, a Maxxair fan drawing 1 amp.
Will adjust the absorption time.
The mppt is part of an easy solar unit which I connected to 230v supply earlier and the battery charger was only putting in about 2 amps instead of the full 25 or so so it’s not just the mppt charging at a low rate.
Interesting. That sounds like there may be a problem in the battery then. Except the stats look good as they are balanced at the float voltage (other than SOC not being correct).
Normally lithium batteries take all power the can get, so it is strange, that they only get 2a with a charger.
Have you the possibility to charge the battery external and measure voltage and amperage dircet at the terminals?
I was wondering about cell swelling. As they behave like that when they are not well.
How old are the batteries?
